1. Field of the Invention
The present invention relates to a tool for imposing tension on pre-existing equipment for pulling pins from the connection of a bogie to an associated vehicle chassis.
2. Description of the Prior Art
Adjustment of trailer weight, as by repositioning a bogie relative to the trailer chassis, is well known. Apparatus has been proposed in the prior art for withdrawing pins locking the bogie to the chassis. Typical prior art arrangements incorporate a lever having a pivot point, there being arms extending laterally from the lever from opposite sides of the pivot point. One or more springs may be provided to bias the lever such that the arms project outwardly from the pivot point, each urging a corresponding pin into aligned holes formed in the trailer chassis and in the bogie.
U.S. Pat. No. 4,286,797, issued to George Mekosh Jr., et al. on Sep. 1, 1981, describes a system which is spring biased to maintain pins in their operative position, locking a bogie to its associated chassis, and employing fluid pressure to counteract the bias, thus extracting the pins. The bogie is then repositioned on the trailer chassis, and pins are replaced in new locations.
Similar devices, although hand operated, are seen in U.S. Pat. Nos. 2,818,272, issued to Manford S. De Lay on Dec. 31, 1957; 2,831,735, issued to John C. Bennett et al. on Apr. 22, 1958; 4,838,566, issued to Bobby G. Baxter et al. on Jun. 13, 1989; and 4,944,522, issued to Bobbie M. Hart on Jul. 31, 1990.
U.S. Pat. No. 4,641,846, issued to Leonard M. Ehrhart on Feb. 10, 1987, discloses a system for releasing the brake system of a trailer when pins holding a bogie to the chassis is in proper, operative condition. Proper orientation of the bogie and trailer chassis releases a valve which maintains braking action to the trailer.
The devices of Mekosh, Jr. '797 and Hart '522 incorporate pneumatically powered servos or the like for rendering the lever based pin puller operable by one person. In each respective case, the pneumatic system is integral to the trailer.
An example of a crank operated tool for exerting a pulling force is seen in U.S. Pat. No. 1,367,094, issued to Vincent Ragona on Feb. 1, 1921. The tool has no spring maintaining the pulling force, nor a clamp for attachment to an associated object.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.